#include <iostream>
#include <thread>
#include <future>
void print()
{
    std::cout << "helloworld\n";
}
int main()
{
    // auto f = std::async(std::launch::deferred, print);
    auto f = std::async(std::launch::async, print);

    std::cout << "main thread" << std::endl;
    // f.get();
    return 0;
}